Bill Paxton passed away last week, and now family members are revealing exclusively to RadarOnline.com the secrets behind his tragic death.

The 61-year-old allegedly suffered a stroke during heart surgery and Jon Otten, who is married to Paxton’s sister, tells the outlet that it came as a complete and utter shock to the family.

An understandably upset Jon said, “We didn’t even know he was going to go into surgery. It’s very tragic and sudden.” Otten claimed, “I’m sure his wife knew, but no one in the extended family knew.”

And although it’s not yet clear what caused the stroke, weeks before his passing Paxton did tell family members that he had suffered valve damage as a result of rheumatic fever when he was only a child.

“We don’t know his condition and how easy it was to fix,” Otten said. “He was healthy from what we knew.”

“There was the main surgery and they went back in to tune it up,” Otten explained. “If you’re going to have heart surgery you have to get it right the first time.”

The devastated relative continues, “We are proud of his legacy. He had quite an outpouring of support from fans and friends. It was quite a celebration of a good life.”